A MICROFLUIDIC ANALYSIS SYSTEM

Description

INTRODUCTION

Field of the Invention

[0001] The invention relates to analysis systems for analysis such as Polymerase Chain Reaction (PCR) analysis to detect the population of rare mutated cells in a sample of bodily fluid and/or tissue.

Prior Art Discussion

[0002] It is known for at least the past decade that cancers have a genetic cause. With the emergence of fast methods of sequencing and the publication of the human genome, the motivation and methods are available to find the genetic causes, both germline and somatic, of the most prevalent cancers. Contemporary oncological research suggests that there is a sequence of mutations that must occur for a cancer to be life-threatening, called the multistage model. Cancer could therefore be diagnosed earlier by detecting these genetic markers thereby increasing the probability of cure. However, even with refining of the sample, the target cells and their DNA are still usually very rare, perhaps one part in 10⁶. The analysis system must therefore be able to perform very effective amplification.

[0003] There are several methods of attempting to identify rare cells in a sample of bio-fluid. A common method is to probe the sample using known genetic markers, the markers being specific to the type of mutation being sought, and then amplify the targets in the sample. If the mutations or chromosomal aberations are present then the amplification can be detected, usually using optical techniques.

[0004] It is also possible, depending on the amplification used, to use the Polymerase Chain Reaction (PCR) to detect the number of mutated cells in the original sample: a number important as firstly, it can be linked to the progress of the cancer and secondly, it provides a quantitative measure with which to diagnose remission. PCR is the enzyme-catalysed reaction used to amplify the sample. It entails taking a small quantity of DNA or RNA and producing many identical copies of it in vitro. A system to achieve a PCR is to process the samples by thermally cycling them is described in US5270183. However, this apparently involves a risk of sample contamination by surfaces in the temperature zones and other channels. Also, US6306590 describes a method of performing a PCR in a microfluidic device, in which a channel heats, and then cools PCR reactants cyclically. US 6670153 also describes use of a microfluidic device for PCR.

[0005] The invention is directed towards providing an improved microfluidic analysis system for applications such as the above.

SUMMARY OF THE INVENTION

[0006] According to the invention, there is provided a biological sample analysis system as set out in claim 1.

[0007] In one embodiment, the analysis stages comprise a thermal cycling stage and an optical detection stage for performance of a polymerise chain reaction.

[0008] In another embodiment, the sample preparation stage comprises a centrifuge for separation of samples from an input fluid and for introduction of the samples to the primary carrier fluid.

[0009] In a further embodiment, the centrifuge comprises a pair of opposed primary carrier fluid channels on either side of a vortex chamber, whereby flow of primary carrier fluid in said channels causes centrifuging of sample in the vortex chamber and flow of sample from the chamber into said channels.

[0010] In one embodiment, contact between the sample and the vortex chamber surface is avoided by wrapping the sample in an initial carrier fluid within the chamber.

[0011] In another embodiment, the controller directs separation in the centrifuge either radially or axially due to gravity according to nature of the input fluid such as blood containing the sample.

[0012] In a further embodiment, the primary carrier fluid velocity is in the range of 1m/s to 20m/s.

[0013] In one embodiment, the thermal cycling stage comprises a microfluidic thermal device comprising a thermal zone comprising a sample inlet for flow of sample through a sample channel while enveloped in the primary carrier fluid, and a thermal carrier inlet for flow of a thermal carrier fluid to heat or cool the sample by heat conduction through the primary carrier fluid.

[0014] In another embodiment, the microfluidic thermal device thermal zone further comprises separate sample and thermal outlets positioned to allow flow of thermal carrier fluid into and out of contact with the primary carrier fluid.

[0015] In a further embodiment, there is at least one pair of opposed thermal carrier inlet/outlet pairs on opposed sides of a sample channel.

[0016] In one embodiment, the thermal cycling stage comprises a plurality of thermal zones.

[0017] In one embodiment, the microfluidic thermal device comprises a plurality of thermal zones in series.

[0018] In another embodiment, the thermal cycling stage comprises a plurality of microfluidic thermal devices in series.

[0019] In a further embodiment, the microfluidic thermal device comprises a closed sample channel for re-circulation of sample with successive heating or cooling in successive thermal zones.

[0020] In one embodiment, the controller directs flow of the thermal and primary carrier fluids to control flowrate of sample by enveloping within the primary carrier fluid and by viscous drag between the thermal carrier fluid and the primary carrier fluid.

[0021] In another embodiment, the primary carrier fluid is biologically non-reactive.

[0022] In a further embodiment, the primary carrier fluid is a silicone oil.

[0023] In one embodiment, the thermal carrier fluid is biologically non-reactive.

[0024] In another embodiment, the thermal carrier fluid is a silicone oil.

[0025] In a further embodiment, the temperatures and flowrates of the carrier fluids are controlled to achieve a temperature ramping gradient of 17°C/sec to 25°C/sec.

DETAILED DESCRIPTION OF THE INVENTION

Brief Description of the Drawings

[0026] The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which: -

Fig. 1 is a diagram of an analysis system of the invention.

Fig. 2 is a diagrammatic plan view of a centrifuge of the system, and Fig. 3 is a simulation diagram showing centrifuging;

Fig. 4 is a perspective view of the main body of a microfluidic heater of the system;

Fig. 5 is a prediction velocity and temperature plot along a thermal stage of the heater;

Fig. 6 is a centre line temperature profile in the flow direction showing fast response of same in the heated zone; and

Fig. 7 is a plan view of an alternative microfluidic heater.

Description of the Embodiments

[0027] Referring to Fig. 1 an analysis system 1 comprises a controller 2 which interfaces with various stages. A carrier fluid supply 4 delivers carrier fluid to a macro pump 5 which delivers it at a high flowrate to a sample preparation stage 6. The latter also receives a bio-fluid sample, and centrifuges the sample in a vortex created by carrier fluid flow, as described in more detail below. Reactants are supplied by a supply 8 to a flow controller 7 which delivers streams of separated DNA with reactants enveloped in carrier fluid to a thermal cycling stage 9. The DNA is amplified in the stage 9 and optically detected by a detection stage 10. Throughout the process the samples are enveloped in a biologically non-reactive carrier fluid such as silicone oil. This avoids risk of contamination from residual molecules on system channel surfaces.

[0028] Referring to Fig. 2 a centrifuge device 20 of the sample preparation stage 6 is illustrated diagrammatically. It comprises opposed carrier supply lines 21 and 22 and a central vortex chamber 23 having a sample inlet out of the plane of the page. The centrifuge 20 operates by primary carrier fluid in the channels 21 and 22 driving sample fluid in the chamber 23 into a vortex via viscous forces at the interface between the two fluids. In this embodiment, the carrier fluid is silicone oil mixed to be neutrally buoyant with the sample.

[0029] The vortex, or centrifuge, is thus established without any mechanical moving parts. The carrier fluid drives a vortex of the sample to be centrifuged thereby avoiding the very many difficulties of designing and operating moving parts at the micro scale, particularly at high rotational speeds. Fig. 3 illustrates the centrifuging activity, the greater density of dots indicating higher flow velocities. The left-hand scale shows the velocity range of 1 m/s to 20 m/s. The sample is wrapped in an initial volume of carrier fluid within the chamber 23 to prevent surface contamination.

[0030] This achieves a continuous throughput micro-centrifuging to suitably extract DNA and RNA from cellular material. The bio-fluid is centrifuged resulting in DNA and other bio-molecules of interest accumulating at the bottom of the chamber, thereby providing an efficient and simple method of manipulating micron and sub-micron quantities of bio-fluid. The DNA and RNA are separated due to the greater weight and viscous resistance of the DNA. Numerical simulations (Fig. 3) of the flow show that tangential velocities of up to 10ms^-1 are generated towards the edge of the vortex core. Calculations reveal this to be equivalent to a rotational speed of almost 20,000 rpm or 2,000g in terms of a centrifugal force. In order to achieve these levels of centrifugal force, the carrier fluid is pumped at speeds of 5ms^-1 through the system. In general, the desired carrier fluid speed is 1 m/s to 20 m/s. The device has further potential to be miniaturized to centrifuge at up to 200,000g, as these levels of force are necessary for efficient separation of RNA and other smaller cellular constituents and bio-molecules.

[0031] Overall, the continuous throughput centrifuge offers many benefits over conventional technology. The device may also function as a fluid mixing device by reversing the flow path of one of the carrier fluid, if such is desired for an application. It is modular in nature, meaning two or more systems can be placed together in any configuration and run by the same control and power source system. The centrifuge 20 has no moving parts thereby allowing excellent reliability compared with a system having moving parts. An important consequence of this feature is that manufacturing this device at the micro-scale using current silicon processing or micro-machining is readily achievable.

[0032] Referring to Fig. 4 a microfluidic thermal device 51 of the stage 9 is shown. It comprises three successive thermal zones 52, 53, and 54. Each zone comprises a sample inlet 60 and an outlet 61 for flow of the bio sample in the primary carrier fluid. There are also a pair of thermal carrier inlets 65 and 66, and a pair of thermal carrier outlets 67 and 68 for each of the three zones. This drawing shows only the main body, there also being top and bottom sealing transparent plates.

[0033] The bio sample which enters the sample inlet 60 of each stage is enveloped and conveyed by the carrier fluid henceforth called the "primary carrier fluid". Thermal carrier fluid is delivered at the inlets 65 and 66 to heat or cool the bio sample via the primary carrier fluid.

[0034] As the sample remains in a low shear rate region of the flow, mass transport by diffusion of sample species is kept to a minimum. The low shear region reduces damage by shear to macro molecules that may be carried by the bio sample. The arrangement of a number (in this case three) of thermal zones in series offers advantages to applications such as the polymerase chain reaction (PCR) where rapid and numerous thermal cycles lead to dramatic amplification of a DNA template strand.

[0035] The device 51 also acts as an ejector pump, in which the velocity and hence the residency time of the sample is controlled by controlling velocity of one or both of the carriers fluids. The carrier flow parameters determine how long the sample remains at the set temperature in each zone. This is often important, as chemical reactions require particular times for completion. The device 51 can therefore be tuned to the required residency times and ramp rates by controlling the carrier velocity.

[0036] Referring to Fig. 5 a predicted velocity contour map at the mid-height plane of a zone channel is shown. Carrier fluid enters through the channels at the top and bottom left of the image and exits through the channels at the top and bottom right of the image. The sample fluid enters and exits through the central channel. The different shadings of this map indicate the velocities, the range being 0.01 m/s to 0.1 m/s.

[0037] In one example, sample fluid enters through the central channel at the left of the image at a temperature of 50°C and is heated to 70°C by the thermal carrier fluid.

[0038] Fig. 6 shows a temperature profile along a longitudinal centreline of a thermal zone. A target temperature of 342 K is achieved within an extremely short distance from entrance, achieving an excellent temperature ramp rate of 20°C/sec over a distance of 0.05m. In general, a ramping of 17 °C/sec to 25 °C/sec is desirable for many applications.

[0039] The following table sets out parameters for one example. A silicone oil, density matched to the density of the bio sample, is used for both of the carrier fluids.

Table 1

Boundary Conditions and Fluid Properties
Overall Channel Dimensions	5mm x 5mm x 200mm
Wall Boundary Condition outside of carrier flow interaction zones	Adiabatic
Heat Transfer Carrier Fluid Inlet temperature	70°C, 90°C, 110°C for each zone
Sample/Transport Carrier Inlet Pressure	0 Pa
Heat Transfer Carrier Fluid Inlet Pressure	0.2Pa
Sample/Transport Carrier Outlet Pressure	1.9Pa
Heat Transfer Carrier Fluid Outlet Pressure	1.7Pa
Mass Diffusivity	1.3 E-12 m2/s
Approximate Temperature Gradient in Zones	20 °C/sec

[0040] Referring to Fig. 7, another microfluidic thermal device, 70, is shown. There are again three thermal zones, however in this case on a generally rectangular closed circuit, with zones 71, 72, and 73. The zones 71 and 73 are on one side and there is only a single zone, 72, on the other side. The thermal carrier fluid is silicone oil, as is the primary carrier fluid. The thermal carrier fluid for the zone 71 is at 68°C, to ramp up the bio sample to this temperature during residency in this zone. The zones 72 and 73 provide outlet temperatures of 95°C and 72°C respectively.

[0041] The optical detection stage 10 is positioned over the microfluidic device 70 to analyse the sample. The silicone oil is sufficiently transparent to detect the fluorescently tagged molecules.

[0042] It will be appreciated that the invention achieves comprehensive control over bio sample flowrate and temperature, with no risk of contamination from device surfaces. The invention also achieves integrated pumping and thermal cycling of the sample without moving parts at the microscale. There are very high throughputs as measured by processing time for one sample.

[0043] The system is expected to have a low cost and high reliability due to the absence of micro scale moving parts. The system also allows independent control and variation of all PCR parameters for process optimisation.

[0044] The invention is not limited to the embodiments described but may be varied in construction and detail.

Claims

1. A biological sample analysis system (11) comprising:

a carrier fluid supply (4);

a sample supply;

a channel;

a sample preparation stage (6, 7) for providing in the channel a flow of sample enveloped in a primary carrier fluid, said primary carrier fluid being biologically non-reactive;

at least one analysis (9, 10) stage for performing analysis of the sample;

a controller (2) for controlling the system, including controlling flow of the sample while enveloped within the primary carrier fluid without the sample contacting a solid surface.

2. A biological sample analysis system as claimed in claim 1, wherein the analysis stages comprise a thermal cycling stage (9) and an optical detection stage (10) for performance of a polymerise chain reaction.

3. A biological sample analysis system as claimed in claim 2, wherein the sample preparation stage (6) comprises a centrifuge (20) for separation of samples from an input fluid and for introduction of the samples to the primary carrier fluid.

4. A biological sample analysis system as claimed in claim 3, wherein the centrifuge comprises a pair of opposed primary carrier fluid channels (21, 22) on either side of a vortex chamber (23), whereby flow of primary carrier fluid in said channels causes centrifuging of sample in the vortex chamber and flow of sample from the chamber into said channels.

5. A biological sample analysis system as claimed in claim 4, wherein contact between the sample and the vortex chamber (23) surface is avoided by wrapping the sample in an initial carrier fluid within the chamber.

6. A biological sample analysis system as claimed in any of claims 3 to 5, wherein the controller directs separation in the centrifuge either radially or axially due to gravity according to nature of the input fluid such as blood containing the sample.

7. A biological sample analysis system as claimed in any of claims 4 to 6, wherein the primary carrier fluid velocity is in the range of 1m/s to 20m/s.

8. A biological sample analysis system as claimed in any of claims 2 to 7, wherein the thermal cycling stage comprises a microfluidic thermal device (51) comprising a thermal zone (52, 53, 54) comprising a sample inlet (60) for flow of sample through a sample channel while enveloped in the primary carrier fluid, and a thermal carrier inlet (65, 66) for flow of a thermal carrier fluid to heat or cool the sample by heat conduction through the primary carrier fluid.

9. A biological sample analysis system as claimed in claim 8, wherein the microfluidic thermal device thermal zone further comprises separate sample (61) and thermal outlets (67, 68) positioned to allow flow of thermal carrier fluid into and out of contact with the primary carrier fluid.

10. A biological sample analysis system as claimed in claim 9, wherein there is at least one pair of opposed thermal carrier inlet/outlet pairs on opposed sides of a sample channel.

11. A biological sample analysis system as claimed in any of claims 8 to 10, wherein the thermal cycling stage comprises a plurality of thermal zones.

12. A biological sample analysis system as claimed in claim 11, wherein the microfluidic thermal device (51) comprises a plurality of thermal zones in series (52, 53, 54).

13. A biological sample analysis system as claimed in any of claims 8 to 12, wherein the thermal cycling stage (9) comprises a plurality of microfluidic thermal devices (51) in series.

14. A biological sample analysis system as claimed in any of claims 8 to 13, wherein the microfluidic thermal device (70) comprises a closed sample channel for re-circulation of sample with successive heating or cooling in successive thermal zones (71, 72, 73).

15. A biological sample analysis system as claimed in any of claim 8 to 14, wherein the controller directs flow of the thermal and primary carrier fluids to control flowrate of sample by enveloping within the primary carrier fluid and by viscous drag between the thermal carrier fluid and the primary carrier fluid.

16. A biological sample analysis system as claimed in claim 1, wherein the primary carrier fluid is a silicone oil.

17. A biological sample analysis system as claimed in any of claims 8 to 12, wherein the thermal carrier fluid is biologically non-reactive.

18. A biological sample analysis system as claimed in claim 17, wherein the thermal carrier fluid is a silicone oil.

19. A biological sample analysis system as claimed in any of claims 8 to 18, wherein the temperatures and flowrates of the carrier fluids are controlled to achieve a temperature ramping gradient of 17 °C/sec to 25°C/sec.

Ansprüche

1. System (11) zur Analyse von biologischen Proben, das umfasst:

eine Trägerfluidzufuhr (4);

eine Probenzufuhr;

einen Kanal;

eine Probenzubereitungsstufe (6, 7) zum Bereitstellen eines Flusses einer Probe im Kanal, die in ein primäres Trägerfluid eingehüllt ist, wobei das primäre Trägerfluid biologisch nicht-reaktiv ist;

zumindest eine Analysestufe (9, 10) zum Durchführen einer Analyse der Probe;

eine Steuereinheit (2) zum Steuern des Systems, darunter das Steuern des Flusses der Probe, während diese innerhalb des primären Trägerfluids eingehüllt ist, ohne dass die Probe eine feste Oberfläche berührt.

2. System zur Analyse von biologischen Proben nach Anspruch 1, wobei die Analysestufen eine Stufe (9) des thermischen Zyklisierens und eine Stufe (10) des optischen Nachweisens für eine Leistung einer Polymerasekettenreaktion umfassen.

3. System zur Analyse von biologischen Proben nach Anspruch 2, wobei die Probenzubereitungsstufe (6) eine Zentrifuge (20) zum Trennen von Proben aus einem Einbringungsfluid und zum Einbringen der Proben in das primäre Trägerfluid umfasst.

4. System zur Analyse von biologischen Proben nach Anspruch 3, wobei die Zentrifuge ein Paar gegenüberliegender Kanäle (21, 22) primären Trägerfluids auf jeder Seite einer Wirbelkammer (23) umfasst, wobei ein Fluss von primärem Trägerfluid in den Kanälen ein Zentrifugieren der Probe in der Wirbelkammer und einen Fluss der Probe aus der Kammer in die Kanäle bewirkt.

5. System zur Analyse von biologischen Proben nach Anspruch 4, wobei ein Kontakt zwischen der Probe und der Oberfläche der Wirbelkammer (23) durch Einhüllen der Probe in ein Ausgangsträgerfluid innerhalb der Kammer vermieden wird.

6. System zur Analyse von biologischen Proben nach einem der Ansprüche 3 bis 5, wobei die Steuereinheit eine Trennung in der Zentrifuge bedingt durch die Schwerkraft gemäß der Beschaffenheit des Einbringungsfluids wie die Probe enthaltendes Blut in der Zentrifuge entweder radial oder axial lenkt.

7. System zur Analyse von biologischen Proben nach einem der Ansprüche 4 bis 6, wobei die Geschwindigkeit des primären Trägerfluids im Bereich von 1 m/s bis 20 m/s liegt.

8. System zur Analyse von biologischen Proben nach einem der Ansprüche 2 bis 7, wobei die Stufe des thermischen Zyklisierens eine mikrofluidische Wärmeeinheit (51) umfasst, die eine Wärmezone (52, 53, 54) umfasst, die einen Probeneinlass (60) für einen Probenfluss durch einen Probenkanal, während in primäres Trägerfluid eingehüllt, und einen Wärmeträgereinlass (65, 66) für einen Fluss eines Wärmeträgerfluids umfasst, um die Probe durch Wärmeleitung durch das primäre Trägerfluid zu erhitzen oder zu kühlen.

9. System zur Analyse von biologischen Proben nach Anspruch 8, wobei die Wärmezone der mikrofluidischen Wärmeeinheit darüber hinaus getrennte Proben- (61) und Wärmeauslässe (67, 68) umfasst, die so ausgelegt sind, dass sie einem Fluss eines Wärmeträgerfluids Herstellung und Trennung eines Kontakts mit dem primären Trägerfluid ermöglichen.

10. System zur Analyse von biologischen Proben nach Anspruch 9, wobei zumindest ein Paar von gegenüberliegenden Wärmeträgereinlass-/-auslasspaaren an gegenüberliegenden Seiten eines Probenkanals vorhanden ist.

11. System zur Analyse von biologischen Proben nach einem der Ansprüche 8 bis 10, wobei die Stufe des thermischen Zyklisierens eine Mehrzahl von Wärmezonen umfasst.

12. System zur Analyse von biologischen Proben nach Anspruch 11, wobei die mikrofluidische Wärmeeinheit (51) eine Mehrzahl von Wärmezonen in Reihe (52, 53, 54) umfasst.

13. System zur Analyse von biologischen Proben nach einem der Ansprüche 8 bis 12, wobei die Stufe des thermischen Zyklisierens eine Mehrzahl von mikrofluidischen Wärmeeinheiten (51) in Reihe umfasst.

14. System zur Analyse von biologischen Proben nach einem der Ansprüche 8 bis 13, wobei die mikrofluidische Wärmeeinheit (70) einen geschlossenen Probenkanal für eine Probenrückführung mit sukzessivem Erhitzen oder Kühlen in sukzessiven Wärmezonen (71, 72, 73) umfasst.

15. System zur Analyse von biologischen Proben nach einem der Ansprüche 8 bis 14, wobei die Steuereinheit einen Fluss der Wärme- und primären Trägerfluide lenkt, um eine Probendurchflussrate durch Einhüllen innerhalb des primären Trägerfluids und durch Reibungswiderstand zwischen dem Wärmeträgerfluid und dem primären Trägerfluid zu steuern.

16. System zur Analyse von biologischen Proben nach Anspruch 1, wobei das primäre Trägerfluid ein Silikonöl ist.

17. System zur Analyse von biologischen Proben nach einem der Ansprüche 8 bis 12, wobei das Wärmeträgerfluid biologisch nicht-reaktiv ist.

18. System zur Analyse von biologischen Proben nach Anspruch 17, wobei das Wärmeträgerfluid ein Silikonöl ist.

19. System zur Analyse von biologischen Proben nach einem der Ansprüche 8 bis 18, wobei die Temperaturen und Durchflussraten der Trägerfluide gesteuert werden, um einen Temperaturanstiegsgradienten von 17 °C/s bis 25 °C/s zu erzielen.

Revendications

1. Système (11) d'analyse d'échantillon biologique comprenant :

une alimentation en fluide porteur (4) ;

une alimentation en échantillon ;

un canal ;

un étage de préparation d'échantillon (6, 7) pour fournir, dans le canal, un flux d'échantillon enveloppé dans un fluide porteur primaire, ledit fluide porteur primaire étant biologiquement non-réactif ;

au moins un étage d'analyse (9, 10) pour réaliser une analyse de l'échantillon ;

un contrôleur (2) pour commander le système, comprenant la commande du flux de l'échantillon lorsqu'il est enveloppé dans le fluide porteur primaire, sans que l'échantillon entre en contact avec une surface solide.

2. Système d'analyse d'échantillon biologique selon la revendication 1, dans lequel les étages d'analyse comprennent un étage de cyclage thermique (9) et un étage de détection optique (10) pour réaliser une réaction en chaîne par polymérase.

3. Système d'analyse d'échantillon biologique selon la revendication 2, dans lequel l'étage de préparation d'échantillon (6) comprend une centrifugeuse (20) pour une séparation d'échantillons à partir d'un fluide d'entrée et pour l'introduction des échantillons dans le fluide porteur primaire.

4. Système d'analyse d'échantillon biologique selon la revendication 3, dans lequel la centrifugeuse comprend une paire de canaux (21, 22) de fluide porteur primaire opposés de chaque côté d'une chambre tourbillonnaire (23), ce par quoi un flux de fluide porteur primaire dans lesdits canaux provoque une centrifugation d'échantillon dans la chambre tourbillonnaire et un flux d'échantillon de la chambre vers lesdits canaux.

5. Système d'analyse d'échantillon biologique selon la revendication 4, dans lequel un contact entre l'échantillon et la surface de la chambre tourbillonnaire (23) est évité par enveloppement de l'échantillon dans un fluide porteur initial à l'intérieur de la chambre.

6. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 3 à 5, dans lequel le contrôleur dirige une séparation dans la centrifugeuse soit radialement soit axialement, en raison de la gravité selon la nature du fluide d'entrée, tel que du sang contenant l'échantillon.

7. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 4 à 6, dans lequel la vitesse du fluide porteur primaire est située dans la plage allant de 1 m/s à 20 m/s.

8. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 2 à 7, dans lequel l'étage de cyclage thermique comprend un dispositif thermique microfluidique (51) comportant une zone thermique (52, 53, 54) comprenant une entrée d'échantillon (60) pour un flux d'échantillon à travers un canal d'échantillon lorsqu'il est enveloppé dans le fluide porteur primaire, et une entrée de porteur thermique (65, 66) pour un flux d'un fluide porteur thermique pour chauffer ou refroidir l'échantillon par conduction thermique à travers le fluide porteur primaire.

9. Système d'analyse d'échantillon biologique selon la revendication 8, dans lequel la zone thermique de dispositif thermique microfluidique comprend en outre des sorties distinctes (67, 68) d'échantillon (61) et thermique positionnées de façon à permettre un flux de fluide porteur thermique dans le fluide porteur primaire et sans contact avec celui-ci.

10. Système d'analyse d'échantillon biologique selon la revendication 9, dans lequel il y a au moins une paire de paires entrée/sortie de porteur thermique opposées sur des côtés opposés d'un canal d'échantillon.

11. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 8 à 10, dans lequel l'étage de cyclage thermique comprend une pluralité de zones thermiques.

12. Système d'analyse d'échantillon biologique selon la revendication 11, dans lequel le dispositif thermique microfluidique (51) comprend une pluralité de zones thermiques (52, 53, 54) en série.

13. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 8 à 12, dans lequel l'étage de cyclage thermique (9) comprend une pluralité de dispositifs thermiques microfluidiques (51) en série.

14. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 8 à 13, dans lequel le dispositif thermique microfluidique (70) comprend un canal d'échantillon fermé pour une recirculation d'échantillon avec un chauffage ou un refroidissement successif dans des zones thermiques successives (71, 72, 73).

15. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 8 à 14, dans lequel le contrôleur dirige un flux de fluides porteurs thermique et primaire pour commander le débit d'échantillon par enveloppement à l'intérieur du fluide porteur primaire et par une traînée visqueuse entre le fluide porteur thermique et le fluide porteur primaire.

16. Système d'analyse d'échantillon biologique selon la revendication 1, dans lequel le fluide porteur primaire est une huile de silicone.

17. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 8 à 12, dans lequel le fluide porteur thermique est biologiquement non-réactif.

18. Système d'analyse d'échantillon biologique selon la revendication 17, dans lequel le fluide porteur thermique est une huile de silicone.

19. Système d'analyse d'échantillon biologique selon l'une quelconque des revendications 8 à 18, dans lequel les températures et les débits des fluides porteurs sont commandés pour atteindre un gradient en rampe de température de 17 °C/s à 25 °C/s.

Drawing